Influence of weathering on adhesion strength of chemically treated and coated Scotch pine

The objective of this study was to evaluate the effect of weathering on adhesion strength of Scotch pine (Pinus sylvestris L.) samples treated with three concentrations of Tanalith-E. Treated samples were also coated with polyurethane, synthetic and water based varnishes prior to 500 h accelerated weathering test. Adhesion strength between varnishing materials and substrate samples was determined employing pull-off type equipment. Based on the findings in this work adhesion strength values of samples decreased with increasing concentration of treatment chemical. The highest average strength value was found as 3.48 MPa for untreated control samples while 2.88 MPa was the lowest average value for the samples treated with Tanalith-E having 9% concentration and coated with water based varnish. Majority of the failures took place within the adhesion line between coating and the substrate with a very limited torn fibers. Results of statistical analysis revealed that samples coated with three different types of varnishes did not show any significant difference from each other at 95% confidence level. It was also found that chemical treatment of the samples adversely influenced their overall adhesion strength characteristics.     

Fatigue Crack Tip Plasticity for Inclined Cracks

The evaluation of the crack tip deformation is essential to the estimation of crack growth under either static or cyclic loading. A 3-D elastic–plastic finite element analysis was developed to simulate the crack tip deformation along mixed mode inclined edge cracks in a steel plate subjected to either monotonic or cyclic loading at selected R-ratios. In this paper, two types of crack configurations were investigated: inclined cracks with equal inclined lengths (EICL) and inclined cracks with equal horizontal projection length (ECHP). The development of the monotonic (Δm) and cyclic (Δc) crack tip plastically zones and the monotonic (CTOD) and cyclic (ΔCTOD) crack tip opening displacements were traced to find the effect of the crack inclination angle, which significantly affected the size and shape of the crack tip plastic zone. The finite element results compared well with the analytical results based on modified Dugdale’s model. It was observed that Mode II has a significant effect on the plastic zone in the case of equal inclined crack length (EICL), i.e., Mode II increases as the crack angle decreases. Also, it is interesting to note that for the EICL case, the magnitude of Δc is delayed to appear with decreasing the inclination angle, for example, for θ?=?90° the cyclic plastic zone appeared at Δσ?=?103.32 MPa, while for θ?=?45° the cyclic plastic zone appeared at Δσ?=?132.84 MPa. Whereas, the variation of monotonic and cyclic plastic zone size in the equal crack horizontal projection (ECHP) case is not affected by the crack inclination angle. Furthermore, it was observed that the static crack tip opening displacement (CTOD) and the cyclic (ΔCTOD) are independent of the crack inclination angle in case of ECHP, due to such cracks take into consideration the effect of inclination angle through its length.     

Xylitol: A Review on Bioproduction,Application, Health Benefits,and Related Safety Issues

Xylitol is a pentahydroxy sugar-alcohol which exists in a very low quantity in fruits and vegetables (plums, strawberries, cauliflower, and pumpkin). On commercial scale, xylitol can be produced by chemical and biotechnological processes. Chemical production is costly and extensive in purification steps. However, biotechnological method utilizes agricultural and forestry wastes which offer the possibilities of economic production of xylitol by reducing required energy. The precursor xylose is produced from agricultural biomass by chemical and enzymatic hydrolysis and can be converted to xylitol primarily by yeast strain. Hydrolysis under acidic condition is the more commonly used practice influenced by various process parameters. Various fermentation process inhibitors are produced during chemical hydrolysis that reduce xylitol production, a detoxification step is, therefore, necessary. Biotechnological xylitol production is an integral process of microbial species belonging to Candida genus which is influenced by various process parameters such as pH, temperature, time, nitrogen source, and yeast extract level. Xylitol has application and potential for food and pharmaceutical industries. It is a functional sweetener as it has prebiotic effects which can reduce blood glucose, triglyceride, and cholesterol level. This review describes recent research developments related to bioproduction of xylitol from agricultural wastes, application, health, and safety issues.     

Analysis of cooling curve to determine the end point of freezing

The cooling curve method used for the measurement of freezing point of food is further analyzed to explore whether it can be used to identify the end point of freezing or glass transition. In this method, slope of the cooling curve is determined and plotted as a function of time to identify the end point of freezing (T′_m). Initially, the slope is decreased and then reached a minimum value, which is identified as the nucleation of ice. Then the slope is increased until the end point of freezing. The end point of freezing is identified when the slope starts to decrease from its highest value or plateau. Sucrose solutions and starch gels were used to measure its T′_m in identifying validity of the proposed method. The measured values of T′_m by the proposed method is very close to the literature values.     

Calibration of an Absolute Radiation Thermometer for Accurate Determination of Fixed-Point Temperatures

For accurate determinations of thermodynamic temperature, NPL has developed its absolute radiation thermometer (ART), which is calibrated traceably against a cryogenic radiometer. This article reviews some of the potential sources of systematic uncertainty present in the calibration and use of ART. In particular, this article is concerned with the evaluation of the size-of-source effect and the lens transmittance, as well as potential differences in the responsivity of a transfer trap detector when calibrated in terms of radiant power and used in irradiance mode.     

Temburong Bridge,Brunei – Design of two cable stayed bridges

The Temburong Bridge Project is a 30 km long dual two‐lane highway crossing over the Brunei Bay. It will connect the relatively isolated Brunei district of Temburong to the other three Brunei districts. The main objective of the project is to stimulate economic growth in the Temburong region by connecting it to the country's airport and ports. The alignment crosses two navigation channels resulting in the need for two cable stayed bridges – the Brunei Channel Bridge (145 m main span) and the Eastern Channel Bridge (260 m main span). The design of these cable stayed bridges is one of the first applications of the Eurocode to a fully concrete cable stayed bridge. Both cable stayed bridges draw on strong Islamic architectural influences from the region to form a tower shape that is unique and instantly recognisable. Temburong Brücke, Brunei – Entwurf von zwei Schrägkabelbrücken Die Temburong Brücke ist eine 30 km lange Verbindung über die Brunei Bucht mit zwei Richtungsfahrbahnen mit je zwei Fahrstreifen. Sie wird den relativ isolierten Distrikt Temburong mit den anderen drei Distrikten Bruneis verbinden. Hauptanliegen des Projekts ist die Stimulierung von ökonomischem Wachstum in der Temburong Region, indem sie an den Flughafen und Seehafen des Landes angebunden wird. Die Trassierung erfordert die Überquerung zweier Schiffahrtsrouten. Dies wird mit der Anordnung zweier Schrägkabelbrücken ermöglicht, der Brunei Channel Brücke (145 m Hauptspannweite) und der Eastern Channel Brücke (260 m Hauptspannweite). Die Bemessung der beiden Brücken stellt eine der ersten Anwendungen des Eurocode auf Schrägkabelbrücken mit Betonüberbau dar. Optisch sind die beiden Brücken geprägt von der islamischen Architektur der Umgebung, die Pylonform ist ein besonderes Erkennungsmerkmal der Brücken.     

Measurement of the surface roughness of wood based materials used in furniture manufacture

The objective of this work was to evaluate surface quality of wood based materials used to manufacture furniture units in Singapore. Various type commercially produced composite panels including particleboard, medium density fibreboard (MDF), plywood in addition to ten different solid wood species which are commonly used in furniture production were considered for the experiments. A stylus type profilometer and 3D image analyzer were employed to determine surface roughness of the samples. Medium density fibreboard (MDF) samples resulted in the smoothest surface with an across the sandmark average roughness (R_a) value of 5.07 μm, while corresponding value for plywood specimens was 8.09 μm among the composite panel samples. In the case of solid wood samples, measurements taken along and across the sandmark from the surface of the specimens measured by the stylus type profilometer, balau had the roughest surface with an R_a value of 9.85 μm across the sandmark followed by beech and walnut. Pine specimens along with ash, cherry and nyatoh resulted in relatively smooth surface values. Correlation between measurements taken by two different methods, namely stylus and 3D scanning showed a good agreement with each other. Based on the findings in this work it appears that both methods can be successfully used to evaluate and to get objective numerical values on surface quality of these samples so that such initial data can be used as quality control tool to have more effective further manufacturing steps in furniture production.     

MQBV: multicast quality of service swarm bee routing for vehicular ad hoc networks

Vehicular ad hoc networks (VANETs) are witnessing in recent years a rapid development for road transmissions and are considered as one of the most important types of next generation networks, in which drivers can have access anywhere and anytime to information. However, vehicles have to deal with many challenges such as the links failures due to their frequent mobility as well as limited degrees of freedom in their mobility patterns. In this paper, we propose a new quality of service multicast and multipath routing protocol for VANETs, based on the paradigm of bee's communication, called multicast quality of service swarm bee routing for VANETs (MQBV). The MQBV finds and maintains robust routes between the source node and all multicast group members. Therefore, the average end‐to‐end delay and the normalized overhead load should be reduced, while at the same time increasing the average bandwidth and the packet delivery ratio. Extensive simulation results were obtained using ns‐2 simulator in a realistic VANET settings and demonstrated the efficiency of the proposed protocol. Copyright © 2013 John Wiley & Sons, Ltd.     

Characterization of nanostructured hydroxyapatite prepared by Nd:YAG laser deposition

Pulsed laser deposition, under dry and water vapor conditions, was employed to synthesize nanostructured hydroxyapatite films by pulsed laser deposition (PLD) of chlorapatite target for the purpose of coating metallic bone implants by this material. A pulsed Nd:YAG laser operating at a wavelength of 1064 nm and emitting 9 ns pulses was used for deposition. AFM microscopy, FTIR spectroscopy, optical microscopy, adhesion and microhardness measurements were conducted to characterize the films. The in vitro test for the synthesized hydroxyapatite was performed using simulated body fluid (SBF). The results showed a successful transformation of the chlorapatite to hydroxyapatite films characterized by all the HAp peaks with 60 nm root mean square roughness, (80–327) nm grain size, and a microhardness of 512 HV.